In Memories of the American Frontier and other writings, Teddy Roosevelt often remarked on his love of birds and their varied song.

The thrashers’ “voluble, cheery notes,” the meadow larks’ “inexpressively touching cadence,” sparrows’ “sprightly singing” and snow buntings’ “merry song and very sweet notes” made the birds “welcome little guests” in his life, to be missed when they disappeared.

As President, he would remind Congress of birds’ utility in agriculture and forestry. Scientists of the Biological Survey, his 1907 State of Union Address noted, “have discovered that 57 species of birds feed upon scale insects — dreaded enemies of the fruit growers.”

Woodpeckers, in destroying the larvae of wood-boring insects could be “so essential to tree life that our forests might not exist without them.” Cuckoos and orioles, quails and sparrows, hawks, owls and various other birds he stated to be “markedly beneficial” in controlling “pests that prey upon the products of husbandry.”

In the century since, loss of natural habitat, invasive species and other threats have taken a toll on bird populations. An Interior Department study, concluded in 2009, found nearly a third of the nation’s 800 bird species endangered, threatened or in significant decline.

Instead of Eastern shorebirds’ or prairie warblers’ song, Secretary Salazaar stated, the decline if not halted could lead to “the silence in forests, fields and backyards that Rachel Carson warned us about,” 50 years ago.

The worst of the causative “other threats,” and its magnitude in the demise of birds, were identified in a new study last month. It involves an animal agent more prolific than kudzu in the eastern landscape. It kills far more birds each year than pesticides and poisons, collisions with windmills, power lines or the windows of homes or automobiles, combined.

It is “that cuddly kitty,” as the New York Times headlined its report on the study by scientists of the U.S. Fish and Wildlife Service and the Smithsonian Conservation Biology Institute.

Domestic cats, whether pets that spend a part of the day outdoors or the unnamed strays and ferals that never leave it, the Times notes, kill a median of 2.4 billion birds and 12.3 billion mammals every year. Most of the latter are native mammals like chipmunks and voles rather than introduced pests like the Norway rat.

The study states that, “free-ranging domestic cats are likely the single greatest source of anthropogenic mortality for U.S. birds and mammals.”

Their predation effect now being so large, and since they also carry human health risks of rabies, hookworm and other diseases, the American Bird Conservancy’s call for action on containing domestic cats seems commendable. Among several possible measures it recommends removal of un-owned cats and keeping the pet kitty indoors.

As the warming climate brings new insects and heavier infestations to gardens, fields and forests, birds’ beneficial work will be needed more than ever. We shouldn’t have to miss the cheery notes of the spring songsters that so delighted President Roosevelt — and brighten our day, too.